Powdery Mildew and Grass Ailments

Powdery Mildew

• Powdery mildew is a common fungal infection. Different varieties of the fungus attack different plants, ranging from roses to squash plants to the grass in your front yard. Powdery mildew is easily recognizable. It begins as a few scattered white spots on infected grass. Over time it spreads until a large patch of your lawn looks as though it has been sprinkled with flour or talcum powder.

Damage

• Powdery mildew rarely manages to kill grass. It is more of a cosmetic problem than a health issue for most lawns. Powdery mildew weakens grass, however, causing it to turn yellow beneath the white powdery coating. Grass thins out, leaving more of the ground visible. As the powdery mildew steals the nutrition grass photosynthesizes for itself, the grass is left vulnerable to other fungal infections. It is also less able to withstand other physical stresses, like too little sunlight or too much or too little water.

Treatment

• Powdery mildew is too mild an infection to need the intervention of a fungicide. Changing watering habits from watering lightly and often to watering deeply and less frequently can help grass recover on its own. Sunlight kills powdery mildew, so clip back overhanging branches to let more sunshine reach infected grass. If the infection does not fade, try spraying the affected area with a mixture of one part milk to nine parts water. If this does not help and the infection worsens, replace the damaged grass.

Considerations

• To avoid powdery mildew and the grass ailments it brings, choose a variety of grass that is resistant to it. Kentucky bluegrass is especially susceptible to it and should be avoided on shady lawns. Make your lawn less at risk for infection by keeping the grass cut short. Remove thatch rather than allowing it to build up. Avoid over-fertilizing your lawn, as that can attract powdery mildew and other fungal infections.